1. Field of the Invention
The present invention relates generally to ventilation devices and systems, and particularly to a ventilation fan with an automatic blade closure mechanism. The mechanism adjusts the blades to a substantially planar configuration when the fan is not in operation, thereby closing off airflow through the ventilation duct and permitting a decorative display to be applied to the essentially continuous surface of the coplanar blades.
2. Description of the Related Art
Built-in ventilation fans in bathrooms, kitchens, and other areas of homes and other structures are well known. Many such fans include some form of closure for the ventilation duct, to prevent relatively warmer or cooler air from flowing into or from the structure when the fan is not operating. These closure devices comprise various forms, e.g., louvers, single hinged panels, etc. These devices are nearly universally installed upon the exterior of the structure, with the blades and other components of the fan being clearly visible in the interior of the structure. At best, some form of grille or guard may be installed across the ventilation duct, primarily to prevent inadvertent contact with the fan while it is in operation.
All of these various fan configurations result in the ventilation duct and its fan, or at least some form of grille or guard, being visible from within the room where the system has been installed. While such a fan having a grille or guard thereover may not be particularly unsightly, it is nevertheless obtrusive and does not blend well with the interior décor of the typical home, office, or other non-industrial building structure.
Thus, a ventilation fan with automatic blade closure mechanism solving the aforementioned problems is desired.